This is a fine example of the quality material that Denon produced in the 70s.
Manufactured between 1978 and 1979, effectively good stuff!
The Denon PMA 400 amplifier (PMA 501 in some regions) is a pre + main amplifier equipped with a PCC system designed to bring out the essence of discs.
The PCC (Phono Crosstalk Canceler) is a device that adds inverted crosstalk to Phono Pickup-type crosstalk and cancels it out. By using the attached tuning damper to operate two switches, it is possible to improve the frequency range most easily perceived by the ear to approximately -40dB.
The power amplifier section consists of a direct-coupled OCL circuit for all amplifier stages, a low-impedance power supply circuit and new power transistors such as the double epitaxial structure and the triple diffusion structure are adopted for the final output stage respectively.
To protect the loudspeakers from errors and accidents, it has a built-in protection circuit with an extremely fast response time and high reliability.
To improve crosstalk caused by interference between channels, mutual interference is reduced by a circuit configuration in which two circuits are separated and by disconnecting the power supply from a high-current power circuit and the power supply from a low-current preamplifier circuit.
To prevent the small signal sent by the turntable from being degraded by wiring or switches, a phono input circuit is used and the input terminal is connected directly to the equaliser amplifier. This reduces the protection wire and stray capacitance and improves the input impedance.
The Denon TU 300 Receiver (TU 501 in some regions) is beautiful, with 2 large VU meters, with a selector for 3 functions:
– level/signal – where the left meter measures the signal strength and the right the level in the station’s BD’s.
– level – where both measure the station’s BD level, left and right channels.
– power out – which measures the amplifier’s output power, left and right channels.
It also has a 3-level attenuator to lower the sensitivity level of the VU’s at higher volumes, which is also useful for more powerful amplifiers.
Having said all that, let’s talk about the sound:
The sound is very good, warm and powerful 70s sound, very good indeed!
I really liked this set!
Specifications – PMA 400:
Power output: 50 watts per channel into 8Ω (stereo)
Frequency response: 5Hz to 100kHz
Total harmonic distortion: 0.05%
Input sensitivity: 2.5mV (MM), 150mV (line)
Signal to noise ratio: 76dB (MM), 100dB (line)
Output: 150mV (line), 1V (Pre out)
Speaker load impedance: 4Ω (minimum)
Dimensions: 430 x 146 x 321mm
Specifications – TU 300:
Type: Mono/Stereo Tuner
Tuning Bands: FM, MW
Tuning Scale: Analogue
FM Tuning Range: 88 to 108 MHz
MW Tuning Range: 525 to 1630 kHz
Sensitivity: 1.8uV (FM), 300uV (MW)
Signal to Noise Ratio: 75dB (FM), 55dB (MW)
Distortion: 0.15% (FM), 0.4% (MW)
Selectivity: 78dB (FM)
Frequency response: 20Hz to 15kHz (FM)
Dimensions: 430 x 146 x 303mm